• Title/Summary/Keyword: Inhibition Factor

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Antimelanogenic Effect of Ligularia fischeri, Solidago virga-aurea, Aruncus dioicus Extracts from Ullung Island in Murine Melanoma Cells (마우스 악성흑색종세포에서 울릉도 곰취, 미역취, 삼나물 추출물의 멜라닌 생성 억제 효과)

  • Kim, Dong-Hee;An, Bong-Jeun;Kim, Se-Gie;Park, Tae-Soon;Park, Gun-Hye;Son, Jun-Ho
    • Journal of Life Science
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    • v.21 no.2
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    • pp.279-285
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    • 2011
  • The objective of the present study was to evaluate the skin whitening effect of the extracts of 3 herbs, Ligularia fischeri, Solidago virga-aurea and Aruncus dioicus, which were collected from Ullung island. Tyrosinase inhibition activities were 33% in pre-fermented extracts and 45% in post-fermented ones. When tyrosinase activities in B16F10 murine melanoma cells were tested, activities in pre- and post-fermented extracts were 41 and 56.5%, respectively. Thus, the post-fermented extracts might have greater skin whitening effects. The protein expression of MITF, TRP-1, TRP-2, and tyrosinase, which are all skin-whitening related transcription factors, showed that both pre- and post-fermented herbs inhibited protein biosynthesis in B16F10 melanoma cells. Post-fermented herb extracts especially showed a greater decrease of protein expressions. The expression of MITF, a regulatory transcription factor, was also decreased by both extracts but was greater in the post-fermented ones. From the results, it can be concluded that the 3 herb extracts from Ullung island may inhibit melanin biosynthesis by the suppression of MITF activity in a signaling pathway. Results indicate that the post-fermented herbs tested in the present study had skin whitening activities and can be used as functional ingredients for food and cosmetic compositions.

The Establishment of Nitrogen Fixation by Cultured Cell-Rhizobium Association Through Tissue Culture Technique in Soybean (대두조직배양세포(大豆組織培養細胞) - Rhizobium에 의(依)한 질소고정력(窒素固定力))

  • Kang, Sang Jae;Park, Woo Churl
    • Current Research on Agriculture and Life Sciences
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    • v.4
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    • pp.27-35
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    • 1986
  • This experiment was carried out to elucidate the factor of nitrogenase formation and to establish the nitrogen fixation system in mixed culture of cultured cells and rhizobia through tissue culture technique using three soybean varieties, Hwangkeum, Namcheon and D 68-0099 as host plants. The results obtained were as follows; The callus was induced in embryo and radicle, but not in hypocotyl. The most favorable callus induction was caused by the individual application of 2,4-D and NAA at the concentration of 2mg/1 and 4mg/1, respectively, but in case of treating both 2,4-D and kinetin, that was done at the concentration of 0.2mg(2,4-D)/0.05mg(kinetin)per liter. The growth of cultured cell was good at the concentration of 2.0mg(2,4-D)/1 and 0.2mg(2,4-D)/0.05mg(kinetin)per liter. When cultured cells were inoculated with R. japonicum 019 and 011, their growthes were considerably inhibited. The addition of single amino acid inhibited the growth of cultured cells. Hwangkeum was inhibited considerably by methionine and leucine. The inhibition of growth by single amino acid can be abolished by the addition of certain amino acids. The differentiation of adventitious root was good at the concentration of 2.0mg 2,4-D and 0.2mg 2,4-D/0.05mg kinetin per liter. Of three host plants tested with 25 R. japonicum strains, Hwangkeum had affinity for 10 strains, Namcheon for 7 strains and D68-0099 for none. The nitrogen fixing abilities of Hwangkeum and Namcheon caused by cultured cell-Rhizobium association were high in strain 019, 007, and in 007 mixed with 119, respectively.

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In Vitro Anti-bacterial and Anti-inflammatory Effects of Six Types of Herb Aqueous Extracts (일부 살충해독유(殺蟲解毒類) 한약의 Staphylococcus aureus에 대한 시험관 내 항균 및 항염 효과)

  • Jang, Se-Ran;Kim, Dong-Chul
    • The Journal of Korean Obstetrics and Gynecology
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    • v.27 no.1
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    • pp.81-100
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    • 2014
  • Objectives: The object of this study was to observe the in vitro anti-bacterial and anti-inflammatory effects of six single aqueous herbal extracts-Quisqualis Fructus (QuF), Meliae Cortex (MeC), Arecae Semen (ArS), Crassirhizomae Rhizoma (CrR), Ulmi Pasta Semen(UlS), Torreyae Semen(ToS)- against Staphylococcus aureus (S. aureus) and Lipopolysaccharide(LPS)-activated Raw 264.7 cells. Methods: Anti-bacterial activities against S. aureus of aqueous extracts of QuF, MeC, ArS, CrR, UlS and ToS were detected using standard agar microdilution methods. In addition, the effects on the cell viability, prostaglandin $E_2$ ($PGE_2$), nitric oxide (NO), tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin (IL)-$1{\beta}$ and IL-6 productions of LPS activated Raw 264.7 cells were detected. The anti-bacterial and anti-inflammatory effects were respectively compared with lincomycin and piroxicam. Results: Minimal Inhibition Concentration (MIC) of aqueous extracts of QuF, MeC, ArS, CrR, UlS and ToS against S. aureus was respectively detected $5.625{\pm}4.075$ (3.125~12.500), $0.332{\pm}0.273$ (0.098~0.782), $1.094{\pm}0.428$ (0.782~1.563), $2.969{\pm}2.096$ (0.782~6.250), $9.375{\pm}4.419$ (3.125~12.500)>25 mg/ml. MIC of lincomycin was detected as $0.469{\pm}0.297$ (0.195~0.782) ${\mu}g/ml$ at same conditions. In addition, $ED_{50}$ against LPS-induced cell viabilities and cytokine releases of QuF, MeC, ArS, CrR, UlS and ToS was as follows - Cell viability: 66.370, 2.908, 1.747, 259.553, 18.150 and 34.160 mg/ml; NO production: 389.486, 0.294, 0.138, 523.060, 45.363 and 49.327 mg/ml; $PGE_2$ production: 114.271, 0.223, 0.046, 243.078, 8.829 and 28.947 mg/ml; TNF-${\alpha}$ production: 406.288, 0.343, 0.123, 9404.227, 125.406 and 140.775 mg/ml; IL-$1{\beta}$ production: 117.178, 0.135, 0.019, 237.451, 7.923 and 19.418 mg/ml; IL-6 production: 31.261, 0.105, 0.055, 128.434, 2.290 and 3.745 mg/ml. ED50 of piroxicam against LPS-induced cell viabilities, NO, $PGE_2$, TNF-${\alpha}$, IL-$1{\beta}$ and IL-6 were detected as 35.179, 6.552, 1.162, 7.273, 7.101 and $5.044{\mu}g/ml$, respectively at same conditions. Conclusions: All six single aqueous herbal extracts showed anti-bacterial effects against S. aureus, in the order of MeC, ArS, CrR, QuF and UlS aqueous extracts except for ToS; they did not showed any anti-bacterial effects (MIC>25 mg/ml). They also showed anti-inflammatory effects against LPS-activated Raw 264.7 cells in the order of ArS, MeC, UlS, ToS, QuF and CrR aqueous extracts. It means that the ArS and MeC will be showed favorable potent anti-bacterial and related anti-inflammatory effects.

Emodin Studies on Anti-inflammatory and Skin Barrier Improvement Activities (Emodin의 항염 및 피부장벽개선 활성 연구)

  • Kim, Se-Gie;Choi, Jae Gurn;Jang, Young-Ah
    • Journal of the Korean Applied Science and Technology
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    • v.38 no.6
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    • pp.1383-1392
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    • 2021
  • It has been reported that emodin, a major pharmacologically active ingredient of herbal medicines such as Polygonum cuspidatum, Polygonum multiflorum, Rheum palmatum, and Aloe vera, is effective in antioxidant, antibacterial, anti-inflammatory, anticancer, and liver protection. In this study, to investigate the potential of emodin to be used as a skin disease and functional material, the activity related to the improvement of inflammation and skin barrier function was confirmed. To observe the anti-inflammatory effect on HaCaT cells, which are human keratinocytes, cytokine inhibition was confirmed by ELISA kit and protein expression by western blot. In HaCaT cells activated with TNF-α (10 ng/mL)/IFN-γ (10 ng/mL), emodin was treated with each concentration (5, 10, 20, 40) µM. As a result, It was confirmed that the production amount of TNF-α, IL-1β and IL-6 decreased as the concentration of emodin increased. In the experimental results on the expression levels of inflammation-related proteins iNOS and COX-2, it was confirmed that 48% of iNOS and 29% of COX-2 were inhibited compared to control at a concentration of 20 µM of emodin. As an indicator of skin barrier function improvement, the mRNA expression level of filaggrin, involucrin, and loricirn and the production amount of filaggrin, involucrin, and loricirn were confirmed. and excellent results were obtained with an emodin concentration-dependent increase. In particular, filaggrin, which was produced twice as much as the control at a concentration of 20 µM, is a protein involved in the formation of NMF, a natural moisturizing factor, and is known to play an important role in moisturizing the stratum corneum. In conclusion, it was confirmed that emodin can be used as a material for improving inflammation and improving skin barrier function, which is part of the potential for use as a skin disease and functional material. It is believed that if additional research is performed in the future, the scope of its application can be further expanded.

Changes in physiologically active ingredients and anti-inflammatory properties of underutilized wild vegetables by complex fermentation using beneficial microorganisms (유용미생물에 의한 저이용 산채류의 복합발효 중 생리활성 성분 및 항염증 변화)

  • Sang-Hyeob Sim;Ha KyoungChoi;Da Eun Lee;Soo Chang Na;Dae Il Hwang;Hyo Bin Oh;Yi Teak Lim;Tae-Young Kim;Dae-Woon Kim
    • Food Science and Preservation
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    • v.31 no.2
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    • pp.287-297
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    • 2024
  • It was confirmed that complex fermentation (CF) was more efficient than single-strain fermentations in inducing changes in the contents of phenolic compounds of Maclura tricuspidate and Pyrus Montana Nakai. A mixture of Maclura tricuspidata, Pyrus montana Nakai, Platycodon grandiflorum and Codonopsis lanceolata were fermented in CF using Aspergillus shirousamii (koji), yeast, and lactic acid bacteria (LAB) for 24 days, and the pH, °Brix, total acidity, anti-oxidant activity, polyphenol content, nitric oxide (NO), and Western blotting of inducible nitric oxide synthase (iNOS), cyclo-oxygenase-2 (COX-2), and tumor necrosis factor-𝛼 (TNF-𝛼) of the sample were determined. There was no significant change in pH and total acidity. °Brix significantly decreased from day 6 onwards. HPLC confirmed that the concentrations of chlorogenic acid, 4-hydrobenzoic acid, vanillic acid, and caffeic acid significantly increased from day 18 during the fermentation. Additionally, DPPH, ABTS radical scavenging activity, total phenol, and total flavonoid were confirmed to be increased until 18 days. NO was significantly inhibited from day 6, along with significant inhibition of iNOS, COX-2, and TNF-a. In conclusion, this study confirmed that CF of low-use (or underutilized) wild vegetables enhances phenolic compounds. It effectively suppresses NO, iNOS, COX-2, and TNF-𝛼, markers of inflammation-related pathogenesis. Altogether, our results suggest that CF of the above plants has a potential anti-inflammatory effect.

Regulatory Mechanism of Vascular Contractility by Extracellular $\textrm{K}^{+}$: Effect on Endothelium-Dependent Relaxation and Vascular Smooth Muscle Contractility (세포 외 $\textrm{K}^{+}$의한 혈관 수축신 조절 기전: 혈관평활근 수축성과 내피세포 의존성 이완에 미치는 영향)

  • 유지영;설근희;서석효;안재호
    • Journal of Chest Surgery
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    • v.37 no.3
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    • pp.210-219
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    • 2004
  • Extracellular $K^{+}$ concentration ([ $K^{+}$]$_{0}$ ) can be increased within several mM by the efflux of intracellular $K^{+}$. To investigate the effect of an increase in [ $K^{+}$]$_{0}$ on vascular contractility, we attempted to examine whether extracellular $K^{+}$ might modulate vascular contractility, endothelium-dependent relaxation (EDR) and intracellular $Ca^2$$^{+}$ concentration ([C $a^2$$^{+}$]$_{i}$ ) in endothelial cells (EC). We observed isometric contractions in rabbit carotid, superior mesenteric, basilar arteries and movse aorta. [C $a^2$$^{+}$]$_{i}$ was recorded by microfluorimeter using Fura-2/AM in EC. No change in contractility was recorded by the increase in [ $K^{+}$]$_{0}$ from 6 to 12 mM in conduit artery such as rabbit carotid artery. whereas resistant vessels, such as basilar and branches of superior mesenteric arteries (SMA), were relaxed by the increase. In basilar artery, the relaxation by the increase in [ $K^{+}$]$_{0}$ to from 1 to 3 mM was bigger than that by the increase from 6 to 12 mM. In contrast, in branches of SMA, the relaxation by the increase in [ $K^{+}$]$_{0}$ to from 6 to 12 mM is bigger than that by the increase from 1 to 3 mM. $Ba^2$$^{+}$ (30 $\mu$M) did not inhibit the relaxation by the increase in [ $K^{+}$]$_{0}$ from 1 to 3 mM but did inhibit the relaxation by the increase from 6 to 12 mM. In the mouse aorta without the endothelium or treated with $N^{G}$_nitro-L-arginine (30 $\mu$M), nitric oxide synthesis blocker, the increase in [ $K^{+}$]$_{0}$ from 6 to 12 mM did not change the magnitude of contraction induced either norepinephrine or prostaglandin $F_2$$_{\alpha}$. The increase in [ $K^{+}$]$_{0}$ up to 12 mM did not induce contraction of mouse aorta but the increase more than 12 mM induced contraction. In the mouse aorta, EDR was completely inhibited on increasing [ $K^{+}$]$_{0}$ from 6 to 12 mM. In cultured mouse aorta EC, [C $a^2$$^{+}$]$_{i}$ , was increased by acetylcholine or ATP application and the increased [C $a^2$$^{+}$]$_{i}$ , was reduced by the increase in [ $K^{+}$]$_{0}$ reversibly and concentration-dependently. In human umbilical vein EC, similar effect of extracellular $K^{+}$ was observed. Ouabain, a N $a^{+}$ - $K^{+}$ pump blocker, and N $i^2$$^{+}$, a N $a^{+}$ - $Ca^2$$^{+}$ exchanger blocker, reversed the inhibitory effect of extracellular $K^{+}$. In resistant arteries, the increase in [ $K^{+}$]$_{0}$ relaxes vascular smooth muscle and the underlying mechanisms differ according to the kinds of the arteries; $Ba^2$$^{+}$-insensitive mechanism in basilar artery and $Ba^2$$^{+}$ -sensitive one in branches of SMA. It also inhibits [C $a^2$$^{+}$]$_{i}$ , increase in EC and thereby EDR. The initial mechanism of the inhibition may be due to the activation of N $a^{+}$ - $K^{+}$pump. activation of N $a^{+}$ - $K^{+}$pump.p.p.p.

Proliferative Properties and Cytokine Secretion of Lung Fibroblast Cell Lines of the Patients with Idiopathic Pulmonary Fibrosis (정상인 및 간질성 폐섬유증 환자들의 폐 병변내 섬유모세포주의 증식양상 및 Cytokine분비능에 관한 연구)

  • Kim, Dong-Soon;Paik, Sang-Hoon;Kong, Kyung-Yup;Kim, Dong-Kwan;Park, Seong-Il;Shim, Tae-Sun;Lim, Chae-Man;Lee, Sang-Do;Koh, Youn-Suck;Kim, Woo-Sung;Kim, Won-Dong
    • Tuberculosis and Respiratory Diseases
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    • v.45 no.1
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    • pp.128-139
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    • 1998
  • Background: It is well known that various cytokines and growth factors secreted mainly from alveolar macrophages do the key role in the pathogenesis of IPF. But recently it has been known that structural cells like fibroblast can also release cytokines. So the phenotypic changes in fibroblasts of IPF may do a role in continuous progression of fibrosis. The aim of this study is to find out whether there is a change in the biologic properties of the lung fibroblasts of IPF. Subjects and Method: The study was done on 13 patients with IPF diagnosed by open or thoracoscopic lung biopsy and 7 control patients who underwent resectional surgery for lung cancer. Lung fibroblast cell lines (FB) were established by explant culture technique from the biopsy or resected specimen Result: Basal proliferation of the fibroblast of IPF(IFB) measured by BrdU uptake tended to be highter than control fibroblast(NFB) (0.212 0.107 vs $0.319{\pm}0.143$, p=0.0922), also there was no significant difference in proliferation after the stimulation with PDGF or 10% serum. On the contrary, the degree of inhibition in proliferation by PGE2 was significantly lower($33.0{\pm}13.1%$) in IFB than control($46.7{\pm}10.0%$, p=0.0429). The IFB secreted significantly higher amount of MCP-l($l574{\pm}1283$ pg/ml) spontaneously than NFB($243{\pm}100$ pg/ml) and also after the stimulation with TGF-$\beta$($3.23{\pm}1.31$ ng/ml vs $0.552{\pm}0.236$ ng/ml, p=0.0012). Similarly IL-8 and IL-6 seretion of IFB was significantly higher than NFB at basal state and with TGF-$beta$ stimulation. But after the maximal stimulation with IL-1,8, no significant difference in cytokine secretion was found between IFB and NFB. Conclusion : Above data suggest that the fibroblasts of IPF were phenotypically changed and these change may do a role in the pathogenesis of IPF.

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Triptolide-induced Transrepression of IL-8 NF-${\kappa}B$ in Lung Epithelial Cells (폐상피세포에서 Triptolide에 의한 NF-${\kappa}B$ 의존성 IL-8 유전자 전사활성 억제기전)

  • Jee, Young-Koo;Kim, Yoon-Seup;Yun, Se-Young;Kim, Yong-Ho;Choi, Eun-Kyoung;Park, Jae-Seuk;Kim, Keu-Youl;Chea, Gi-Nam;Kwak, Sahng-June;Lee, Kye-Young
    • Tuberculosis and Respiratory Diseases
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    • v.50 no.1
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    • pp.52-66
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    • 2001
  • Background : NF-${\kappa}B$ is the most important transcriptional factor in IL-8 gene expression. Triptolide is a new compound that recently has been shown to inhibit NF-${\kappa}B$ activation. The purpose of this study is to investigate how triptolide inhibits NF-${\kappa}B$-dependent IL-8 gene transcription in lung epithelial cells and to pilot the potential for the clinical application of triptolide in inflammatory lung diseases. Methods : A549 cells were used and triptolide was provided from Pharmagenesis Company (Palo Alto, CA). In order to examine NF-${\kappa}B$-dependent IL-8 transcriptional activity, we established stable A549 IL-8-NF-${\kappa}B$-luc. cells and performed luciferase assays. IL-8 gene expression was measured by RT-PCR and ELISA. A Western blot was done for the study of $I{\kappa}B{\alpha}$ degradation and an electromobility shift assay was done to analyze NF-${\kappa}B$ DNA binding. p65 specific transactivation was analyzed by a cotransfection study using a Gal4-p65 fusion protein expression system. To investigate the involvement of transcriptional coactivators, we perfomed a transfection study with CBP and SRC-1 expression vectors. Results : We observed that triptolide significantly suppresses NF-${\kappa}B$-dependent IL-8 transcriptional activity induced by IL-$1{\beta}$ and PMA. RT-PCR showed that triptolide represses both IL-$1{\beta}$ and PMA-induced IL-8 mRNA expression and ELISA confirmed this triptolide-mediated IL-8 suppression at the protein level. However, triptolide did not affect $I{\kappa}B{\alpha}$ degradation and NF-$_{\kappa}B$ DNA binding. In a p65-specific transactivation study, triptolide significantly suppressed Gal4-p65T Al and Gal4-p65T A2 activity suggesting that triptolide inhibits NF-${\kappa}B$ activation by inhibiting p65 transactivation. However, this triptolide-mediated inhibition of p65 transactivation was not rescued by the overexpression of CBP or SRC-1, thereby excluding the role of transcriptional coactivators. Conclusions : Triptolide is a new compound that inhibits NF-${\kappa}B$-dependent IL-8 transcriptional activation by inhibiting p65 transactivation, but not by an $I{\kappa}B{\alpha}$-dependent mechanism. This suggests that triptolide may have a therapeutic potential for inflammatory lung diseases.

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Role of PI3K/Akt Pathway in the Activation of IκB/NF-κB Pathway in Lung Epithelial Cells (폐 상피세포에서 PI3K/Akt 경로가 IκB/NF-κB 경로의 활성화에 미치는 영향)

  • Lee, Sang-Min;Kim, Yoon Kyung;Hwang, Yoon-Ha;Lee, Chang-Hoon;Lee, Hee-Seok;Lee, Choon-Taek;Kim, Young Whan;Han, Sung Koo;Shim, Young-Soo;Yoo, Chul-Gyu
    • Tuberculosis and Respiratory Diseases
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    • v.54 no.5
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    • pp.551-562
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    • 2003
  • Background : NF-${\kappa}B$ is a characteristic transcriptional factor which has been shown to regulate production of acute inflammatory mediators and to be involved in the pathogenesis of many inflammatory lung diseases. There has been some evidence that PI3K/Akt pathway could activate NF-${\kappa}B$ in human cell lines. However, the effect of PI3K/Akt pathway on the activation of NF-${\kappa}B$ varied depending on the cell lines used in the experiments. In this study we evaluated the effect of PI3K/Akt pathway on the activation of NF-${\kappa}B$ in human respiratory epithelial cell lines. Methods : BEAS-2B, A549 and NCI-H157 cell lines were used in this experiment. To evaluate the activation of Akt activation and I${\kappa}B$ degradation, cells were analysed by western blot assay using phospho-specific Akt Ab and $I{\kappa}B$ Ab. To block PI3K/Akt pathway, cells were pretreated with wortmannin or LY294002 and transfected with dominant negative Akt (DN-Akt). For IKK activity, immune complex kinase assay was performed. To evaluate the DNA binding affinity and transcriptional activity of NF-${\kappa}B$, electrophoretic mobility shift assay (EMSA) and luciferase assay were performed, respectively. Results : In BEAS-2B, A549 and NCI-H157 cell lines, Akt was activated by TNF-$\alpha$ and insulin. Activation of Akt by insulin did not induce $I{\kappa}B{\alpha}$ degradation. Blocking of PI3K/Akt pathway via wortmannin/LY294002 or DN-Akt did not inhibit TNF-$\alpha$-induced $I{\kappa}B{\alpha}$ degradation or IKK activation. Inhibition of PI3K/Akt did not affect TNF-$\alpha$-induced NF-${\kappa}B$ activation. Overexpression of DN-Akt did not block TNF-$\alpha$-induced transcriptional activation of NF-${\kappa}B$, but wortmannin enhanced TNF-$\alpha$-induced in NF-${\kappa}B$ transcriptional activity. Conclusion : PI3K/Akt was not involved in TNF-$\alpha$-induced $I{\kappa}B{\alpha}$ degradation or transcriptional activity of NF-${\kappa}B$ in human respiratory epithelial cell lines.

Effects of insulin and IGF on growth and functional differentiation in primary cultured rabbit kidney proximal tubule cells - Effects of IGF-I on Na+ uptake - (초대배양된 토끼 신장 근위세뇨관세포의 성장과 기능분화에 대한 insulin과 IGF의 효과 - Na+ uptake에 대한 IGF-I의 효과 -)

  • Han, Ho-jae;Park, Kwon-moo;Lee, Jang-hern;Yang, IL-suk
    • Korean Journal of Veterinary Research
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    • v.36 no.4
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    • pp.783-794
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    • 1996
  • It has been suggested that ion transport systems are intimately involved in mediating the effects of growth regulatory factors on the growth of a number of different types of animal cells in vivo. The functional importance of the apical membrane $Na^+/H^+$ antiporter in the renal proximal tubule is evidenced by estimates that this transporter mediates the reabsorption of approximately one third of the filtered load of sodium and the bulk of the secretion of hydrogen ions. This study was designed to investigate the pathway utilized by IGF-I in regulating sodium transport in primary cultured renal proximal tubule cells. Results were as follows : 1. $Na^+$ was observed to accumulate in the primary cells as a function of time. Raising the concentration of extracellular NaCl induced an decrease in $Na^+$ uptake compared with control cells in a dose dependent manner. The rate of $Na^+$ uptake into the primary cells was about two times higher in the absence of NaCl($40.11{\pm}1.76pmole\;Na^+/mg\;protein/min$) than in the presence of 140mM NaCl($17.82{\pm}0.94pmole\;Na^+/mg\;protein/min$) at the 30 minute uptake. 2. $Na^+$ uptake was inhibited by IAA($1{\times}10^{-4}M$) or valinomycin($5{\times}10^{-6}M$) treatment($50.51{\pm}4.04$ and $57.65{\pm}2.27$ of that of control, respectively). $Na^+$ uptake by the primary proximal tubule cells was significantly increased by ouabain($5{\times}10^{-5}M$) treatment($140.23{\pm}3.37%$ of that of control). When actinomycin D($1{\times}10^{-7}M$) or cycloheximide($4{\times}10^{-5}M$) was applied, $Na^+$ uptake was decreased to $90.21{\pm}2.39%$ or $89.64{\pm}3.69%$ of control in IGF-I($1{\times}10^{-5}M$) treated cells, respectively. 3. Extracellular cAMP decreased $Na^+$ uptake in a dose-dependent manner($10^{-8}-10^{-4}M$). IBMX($5{\times}10^{-5}M$) also inhibited $Na^+$ uptake. Treatment of cells with pertussis toxin(50pg/ml) or cholera toxin($1{\mu}g/ml$) inhibited $Na^+$ uptake. Extracellular PMA decreased $Na^+$ uptake in a dose-dependent manner(1-100ng/ml). 100 ng/ml PMA concentration significantly inhibited $Na^+$ uptake in IGF-I treated cells. However, staurosporine($1{\times}10^{-7}M$) had no effect on $Na^+$ uptake. When PMA and staurosporine were added together, the inhibition of $Na^+$ uptake was not observed. In conclusion, sodium uptake in primary cultured rabbit renal proximal tubule cells was dependent on membrane potentials and intracellular energy levels. IGF-I stimulates sodium uptake through mechanisms that involve some degree of de novo protein and/or RNA synthesis, and cAMP and/or PKC pathway mediating the action mechanisms of IGF-I.

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